Dr Oruba lec3 1 Microbial Metabolism Its the growth nutrition And metabolism OF BACTERIA What does physiology means Metabolism Metabolism Is the sum of all chemical reactions in the body ID: 778253
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Slide1
Medical Microbiology Dr. Oruba lec.3
1
Slide2Microbial Metabolism
Slide3It’s the growth, nutrition, Andmetabolism OF BACTERIAWhat does physiology means ?
Slide4MetabolismMetabolism: Is the sum of all chemical reactions in the body. metabolism is divided into two types of classes: catabolism and anabolism.
Slide5-Catabolic reactions supply both energy and the basic structural elements for the synthesis of specific bacterial molecules. -In the anabolic reactions , the energy requirement is consumed in form of light or chemical energy—by photosynthetic or chemosynthetic bacteria, respectively.
Slide66Metabolism; It includes all the chemical reactions that occur in the cell, which include two processes;1- Anabolism; all the chemical reactions that building up of cell structures and constituents where these reactions require energy.
2- Catabolism; all the chemical reactions that lead to the breaking down of macromolecules in to small and simpler ones where it leads to production of energy.Oxidation of carbohydrates to form carbon and energy source…………………..Hexoses
and
pentoses
are the major
monosaccharides
sources………
Funneling into the major pathways……..
Degradation of bigger molecules into smaller ones………..
Formation of end products……
Dr SalehMicrobiology7
Assimulation (anabolism): energy-requiring
Dissimulation
(catabolism): energy-acquiring
Focal metabolites:
metabolic intermediates that link anabolic and catabolic pathways.
Glycolysis
Pentose phosphate pathway
TCA cycle
Respiration (aerobic and anaerobic)
Fermentation
Slide88
Slide99
Slide10CarbonStructural organic molecules, energy sourceChemoheterotrophs use organic carbon sourcesAutotrophs use CO2The Requirements for Growth: Chemical Requirements
Slide1111 *According to the source of energy, organisms are divided into two groups;Phototrophs; convert radiant energy from sunlight into chemical energy…..Chemotrophs; transfer energy from organic or inorganic molecules into specific energy molecules………
*According to the source of carbon, organisms are divided into two groups;Heterotrophs; use organic or inorganic chemicals( other than CO2) as a source of carbon…Lithotrophs
(
autotrophs
); their source of carbon is by fixation of CO
2
from the atmosphere….
Therefore, organisms in general, are divided into four groups;
Nutritional group
Carbon source
Energy source
Examples
1-
2-
3-
4-
Chemolithotrophs
Chemoheterotrophs
Photolithotrophs
photoheterotrophs
CO
2
Org.comp
.
CO
2
Org. comp.
Chemicals
Chemicals
Light
Light
Sulfur bact., iron bact.,….
Higher animals including human, most eukaryotic organisms,….
Green plants, most algae…..
Some
cyanobact
., some algae.
Slide1313On the basis of the kind of electron acceptor, energy, in the form of ATP, in microorganisms is produced by 3 ways;Fermentation; it is an oxidation-reduction process for the production of energy, where the electron donors and electron acceptors both are organic compounds….and the amount of energy produced is only 2 ATP.Aerobic respiration; it is an oxidation-reduction process for production of energy where the electron donors are either organic or inorganic compounds, and the final electron acceptor is oxygen….and the amount of energy produce is 36 ATP.Anaerobic respiration
; it is an oxidation-reduction process, where the electron donors are either organic or inorganic compounds, and the electron acceptor is inorganic molecules, such as; NO-3, NO-2, SO4
- -
, CO
2
, H
2
S, …….etc. The amount of energy produced is only
1 or 2 ATP.
14*Mechanism of electron transport and oxidative phosphorylation is basically the same in aerobic and anaerobic respiration, but differs in the followings:Type of the electron acceptor..Amount of the energy producedThe terminal enzyme component in electron transport system in
anaerobes is not cytochrome oxidase but other enzymes such as reductases…
Slide15NitrogenIn amino acids, proteinsMost bacteria decompose proteinsSome bacteria use NH4+ or NO3A few bacteria use N2 in nitrogen fixation
SulfurIn amino acids, thiamine, biotinMost bacteria decompose proteinsSome bacteria use SO42
or H
2
S
Phosphorus
In DNA, RNA, ATP, and membranes
PO
4
3
is a source of phosphorus
The Requirements for Growth: Chemical Requirements
Slide16Trace ElementsInorganic elements required in small amountsUsually as enzyme cofactorsThe Requirements for Growth: Chemical Requirements
Slide17Organic Growth FactorsOrganic compounds obtained from the environmentVitamins, amino acids, purines, pyrimidinesThe Requirements for Growth: Chemical Requirements
Slide18Complex polysaccharide Used as solidifying agent for culture media in Petri plates, slants, and deepsGenerally not metabolized by microbesLiquefies at 100°CSolidifies ~40°CAgar
Slide19Culture Medium: Nutrients prepared for microbial growthSterile: No living microbesInoculum: Introducing of microbes into mediumCulture: Microbes growing in/on culture mediumCulture Media
Slide20Sterile Mannitol Salt Agar
Slide21Streak Plate
Figure 6.10a, b
Slide22Nasal swab sample on Mannitol Salt Agar (MSA). Non-mannitol fermenter on left. Mannitol fermenter on right, viewed from bottom
Slide23References: 1- Jawetz, Melnick, & Adelberg’s.( 2013). Medical Microbiology (Twenty-Sixth Edition).2- Kenneth Todar. (2008).Todar’s Online Textbook of Bacteriology ,University of Wisconsin. 23
Slide24Thank you